I normally find out if an action has been taken or not. I frequently watch the modlog for any bans/deletions when an action does appear on there, or I always find out when I revisit the thread/board. I've kind of got to know when most staff come on and certain other members. Just keep up the reporting, if you have a good score >40%/60% then there isn't too much to worry about. The ones I do report are normally straight forward and you know that they are going to be moderated, but the ones that are controversial and aren't very regular. I'm sure if a moderator deals with your posts daily and recognises your not strong in one area, they'll provide some constructive criticism. If you have a good score you have a pretty good understanding of the moderation policy and what opinions the moderators share with you, so a feedback feature isn't that necessary in my opinion. Although, it could be a neat feature it the future.
Well first thing I want to address, is that the indicator isn't used for people to get competitive over. If you have 50 reports with 50% accuracy, that is still highly appreciated.
Reporting posts almost seems like it's a status thing now
If you have a question, send a pm to a moderator and ask. They will probably be able to give you a more thorough answer to a range of questions than you could extrapolate from accuracy %. Admins are always swamped, so my advice would be to shoot a pm off to the local moderator of the thread in question, or a global moderator. Always happy to fire off a pm to someone not trying to start some drama. Questions are a highlight of my day
I've got to back this up, I've sent several questions over time to various different moderators and nearly all of them have got back to me with everything I wanted, only one/two haven't due to what I assume is that they are busy. I contacted Salty in particular and he cleared up everything I asked and also gave me a few ideas on reporting habits.
Here's a quote for dear old Maged, which might interest you:
Your success rate doesn't actually matter all that much. If you're above 60%, we'll teach you the rest once you become a mod. As long as you can maintain that, quantity of reports is much more important than quality. Specifically, we're looking for people who report things during time periods where the reports aren't immediately acted on, because that indicates a need for additional moderators for that time block. People who report things during those time are far more likely to be chosen, and you're more likely to report during those times if you report more in general.